The National Stone, Sand and Gravel Association designed the NSSGA INSTA-GUIDES to
provide the industry salespeople with a simple, basic and instant overview of sales issues
within the industry. The NSSGA INSTA-GUIDES will show you where to find detailed and
expanded background information highlighting a particular selling topic.
 

Topic #5
Selling Aggregate for Use in Hot Mix Asphalt Pavements
This INSTA-GUIDE will:
1. Define hot mix asphalt pavements.
2. Discuss aggregate quality.
3. Highlight liquid asphalt.
4. Discuss customer requirements.
5. Provide more detailed hot mix asphalt pavement references.
 

1. The Hot Mix Asphalt Pavement
In its simplest form, the hot mix asphalt pavement is a proportioned combination of
aggregate and asphalt that’s been heated in a central mixing plant. It is then transported
to a project and spread and compacted on a road surface before cooling. Typically,
aggregate comprises 93 – 96% of the paving mixture and the “liquid” asphalt comprises
the remaining 4 – 7% (depending on the size and grading of the aggregate).
 

2. Liquid Asphalt
Liquid asphalt is derived from distilling crude oil and is the heavy residue remaining
after other petroleum products have been removed.
 

3. Aggregate Quality
Feature Advantage Benefit
Size and
consistency
Less problems attaining
compaction
Lower rolling cost better
quality pavement
Cubicle particle
shape-coarse
aggregate
Better stability Lower cost, higher quality
pavement, improved skid
resistance
Cubicle particle
shape-fine
Aggregate
Higher strength Lower cost, higher quality
pavement, putting resistance
Low moisture Less moisture to dry Lower drying costs,
stripping resistance
Absorption Lower absorption, less asphalt
used in the mix
Lower cost mix if lower
absorption
Specific Gravity Lower specific gravity, more
volume per ton
More cubic foot of hot mix
per ton
 

4. Customer Requirements
The hot mix asphalt pavement buyers usually know just what they want. So, here are a
few things you should know:
A. Products must be consistent from load to load. Gradation changes can often be
accommodated if they’re acknowledged before the asphalt mix is produced.
B. Low moisture is desirable to reduce drying costs.
C. Excessive dust (-200 sieve) can be a problem in an asphalt mix. If the surface of
the coarse aggregate is coated, it will interfere with the bond between asphalt
and the coarse aggregate.
D. Absorption of the aggregate will affect the hot mix asphalt producer’s cost. A
higher absorption will require more asphalt liquid.
E. Specific gravity of the aggregate will give different results. A lower specific
gravity will result in a higher volume of final mix. This would be a lower cost
mix to the customer due to larger area surfaced per ton.
 

5. Asphalt/Concrete Pavement References
Numerous articles have been published on this subject.
A. NSSGA’s Aggregate Handbook
B. NSSGA’s Aggregate Library
C. Publications From
i. NSSGA
ii. International Center for Aggregates Research
iii. National Asphalt Pavement Association
iv. National Center for Asphalt Technology
v. Asphalt Institute